添加了树的接口

tree/avlkey/avlkey.go

@@ -1,8 +1,10 @@
 package avlkey
 
 import (
-	"github.com/474420502/focus/compare"
 	"github.com/davecgh/go-spew/spew"
+
+	"github.com/474420502/focus/compare"
+	"github.com/474420502/focus/tree"
 )
 
 type Node struct {
@@ -35,6 +37,10 @@ func New(Compare compare.Compare) *Tree {
 	return &Tree{Compare: Compare, iter: NewIteratorWithCap(nil, 16)}
 }
 
+func assertImplementation() {
+	var _ tree.IBSTreeKey = (*Tree)(nil)
+}
+
 func (tree *Tree) String() string {
 	if tree.size == 0 {
 		return ""